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05-25-2003 | 11:30 PM
#1
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From: Mosby, NORWAY
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Hi folks!
Today my old autogyro finally took to the air! I built the thing some 12-15 years ago and tried it back then, but it was sadly underpowered and the project stranded for many years. However, recently I found out I'd give it another shot, and today it finally took to the sky.
The gyro is designed by L. Holmgren from Sweden and is called "Gyrofighter". It has a 44" 4-blade rotor and uses a rotorhead made from Delrin and patented back in 1985 by the same L. Holmgren. Controls are rudder and elevons ( all tail.) For propulsion I use an old Saito .45 4-stroke I had lying around.
Now down to business. I said it flew, but I had the impression that it lacked a lot when it came to rotor efficiency. It had to be flown at full speed almost all the time, and it used half the county to get airborne even though we gave it a good prespin with the starter from my fieldbox. I'll admit it was a calm day with no wind and a little rain, but I still feel that 50 - 60 yds. for take-off is a little bit too much.
This leads me to thinking maybe I should get some more efficient blades, and on RCU everybody talks about how fantastic the SG6042 profile is. This sounds great to me, only problem beeing; I can't find any details, scetches or anything concerning this profile anywhere.
Please, can somebody help me!
Today my old autogyro finally took to the air! I built the thing some 12-15 years ago and tried it back then, but it was sadly underpowered and the project stranded for many years. However, recently I found out I'd give it another shot, and today it finally took to the sky.
The gyro is designed by L. Holmgren from Sweden and is called "Gyrofighter". It has a 44" 4-blade rotor and uses a rotorhead made from Delrin and patented back in 1985 by the same L. Holmgren. Controls are rudder and elevons ( all tail.) For propulsion I use an old Saito .45 4-stroke I had lying around.
Now down to business. I said it flew, but I had the impression that it lacked a lot when it came to rotor efficiency. It had to be flown at full speed almost all the time, and it used half the county to get airborne even though we gave it a good prespin with the starter from my fieldbox. I'll admit it was a calm day with no wind and a little rain, but I still feel that 50 - 60 yds. for take-off is a little bit too much.
This leads me to thinking maybe I should get some more efficient blades, and on RCU everybody talks about how fantastic the SG6042 profile is. This sounds great to me, only problem beeing; I can't find any details, scetches or anything concerning this profile anywhere.
Please, can somebody help me!
05-26-2003 | 05:34 AM
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From: Wimauma, FL
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Hi Sverre,
I have attached a picture of the SG6042 blade profile. For a 5 to 7 lb. gyro I use about a 25" long by 2.5" wide blade. You can make the blades from either 3/16" thick or 1/4" thick material and should be about right. If your blades are lite, 50g to 80g they will spin up real fast with just a little pre-spin. Most of my blades are slightly over 100 g and I pre-spin them with an electric drill. By pre spinning them if everything else is set up correctly your chance of success is much better. If you make the blades from balsa, add a little weight at the tips and you will have more stability.
Good luck, Attach a picture. Best taken before you fly.
Phil
I have attached a picture of the SG6042 blade profile. For a 5 to 7 lb. gyro I use about a 25" long by 2.5" wide blade. You can make the blades from either 3/16" thick or 1/4" thick material and should be about right. If your blades are lite, 50g to 80g they will spin up real fast with just a little pre-spin. Most of my blades are slightly over 100 g and I pre-spin them with an electric drill. By pre spinning them if everything else is set up correctly your chance of success is much better. If you make the blades from balsa, add a little weight at the tips and you will have more stability.
Good luck, Attach a picture. Best taken before you fly.
Phil
05-26-2003 | 05:51 AM
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From: Wimauma, FL
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Hi Sverre,
have attached another picture of the ends of a couple of blades. It's not critical but I sort of round the ends off.
Don't worry about 50 or 60 yrs to get off the ground. I have gyros here in Florida that last winter would get off the ground in about 5 ft with a 5 mph wind. Now, at 98 degrees and high humidity, I'm lucky just to get off the ground.
Phil
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Sverre
have attached another picture of the ends of a couple of blades. It's not critical but I sort of round the ends off.
Don't worry about 50 or 60 yrs to get off the ground. I have gyros here in Florida that last winter would get off the ground in about 5 ft with a 5 mph wind. Now, at 98 degrees and high humidity, I'm lucky just to get off the ground.
Phil
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Sverre
05-26-2003 | 07:07 AM
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From: Mosby, NORWAY
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Hi Phil!
Thanks a lot for your help. This ought to do it. I'm also relieved to hear that the long take-off roll is no need to worry about.
I will post a picture as soon as I get my camera back from repair.
By the way; I agree with the statement from 'Dickybird' in another thread on this forum: You're the man!
Thanks again!
Thanks a lot for your help. This ought to do it. I'm also relieved to hear that the long take-off roll is no need to worry about.
I will post a picture as soon as I get my camera back from repair.
By the way; I agree with the statement from 'Dickybird' in another thread on this forum: You're the man!
Thanks again!
